A Study on the Blue-green Algal Toxin of the Sonaktong Reservoir

Algae > Volume 11(1); 1996 > Article

Algae 1996;11(1): 149-154.

Mee Jeung Park, In Young Hwang, Ae Ran Choi, Jin Ae Lee

Department of Environmental Science, Inje University

ABSTRACT

We report the presence of a microcystin-type toxin in the field algal communities of the Sonaktong Reservoir. The toxin of the algal sample was identified to be a microcystin-type toxin, closely related to microcystin-LR. The algal samples were obtained in July and August 1995 from the bloom materials composed predominantly of Microcystis aeruginosa. The peak shape and retention time of HPLC chromatogram of purified materials were identical to those of an authentic microcystin-LR. The amino acid analysis of an authentic microcystin-LR and the algal sample did exhibit six amino acids in common, but not the same molar ratio. The concentration of the microcystin-type toxin in the bloom material was between 335 μg/g dry wt and 823 μg/g dry wt. There was positive relation among toxin concentrations and chlorophyll a concentrations of the bloom material. However, relations among toxin concentration and physico-chemical environmental parameters of water column such as surface temperature, dissolved oxygen, conductivity and pH were not significant. EC sub(50) of the microcystin-type toxin was in the range from 0.41 to 0.92 mg dry wt/ml D.W. by Microtox super(TM) Toxicity Test. The algal cells was toxic in mouse bioassay with an LD sub(50), i.p. of 150-700 mg/kg body wt.

Key words: microcystin, Microcystis aeruginosa, algal toxin, blue-green algae, Sonaktong Reservoir